Language/Expressions/Equality/evaluation_super_t02.dart

/*
 * Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 * for details. All rights reserved. Use of this source code is governed by a
 * BSD-style license that can be found in the LICENSE file.
 */
/**
 * @assertion Evaluation of an equality expression ee of the form super == e
 * proceeds as follows:
 * • The expression e is evaluated to an object o.
 * • If either this or o is null, then ee evaluates to evaluates to true if both
 *   this and o are null and to false otherwise. Otherwise ee is equivalent to
 *   the method invocation super.==(o).
 * @description Checks that if nnbd is turned on and [o] is [null], the operator
 * super [==(o)] is not called and "type 'Null' is not a subtype of type
 * 'Object'" exception appears.
 * @author msyabro
 */

import '../../../Utils/expect.dart';

class S {
  operator ==(other) {
    Expect.fail('operator== invoked with $other argument');
    return false;
  }
}

class C extends S {
  test() {
    dynamic n = null;
    Expect.throws(() { super == n; });
  }
}

main() {
  new C().test();
}